Was told by an officer on a recent HAL cruise that they will occasionally allow family members to visit in port. This is strictly up to the Captain- some allow, some don't. He said that the current Captain on our ship absolutely forbids any guests at any time (the many times we saw the Captain he never looked very happy).
He did say that if the crew wanted to visit another HAL ship in port (to see friends) they needed to be in uniform to board the other ship.